The Identification of l-α-Amino-δ-hydroxyvaleric Acid and l-Homoserine in Jack Bean Seeds (Canavalia ensiformis)

Biosynthesis of the polyoxins, nucleoside peptide antibiotics: biosynthetic pathway for 5-O-carbamoyl-2-amino-2-deoxy-L-xylonic acid (carbamoylpolyoxamic acid)

“…Since the above experiments strongly support the intermediacy of glutamate-7-semialdehyde, the next logical intermediate may be a-amino-ó-hydroxyvalerate. The presence of this amino acid in some plants was reported (Thompson et al, 1964;Dunnil and Fowden, 1967). Further, -hydroxy--amino acid dehydrogenase was extracted from Neurospora crassa Vogel, 1957, 1959).…”

“…The present study has established the biosynthetic pathway for the CPOAA moiety of the polyoxins, as illustrated in Scheme II. The presence of free AHV was demonstrated in soybean seeds (Thompson et al, 1964) and in a number of Astragalus species (Dunnill and Fowden, 1967). Also, cv-hydroxy-a-amino acid dehydrogenase, which catalyzes the reversible conversion of a-amino-5-hydroxyvaleric acid and -amino-e-hydroxycaproic acid to the respective -semialdehyde was partially purified Vogel, 1957, 1959).…”

“…Finding the enzyme, -hydroxy-a-amino acid dehydrogenase from Neurospora crassa Vogel, 1957, 1959) and the occurrence of a-amino-5-hydroxyvaleric acid in a nonprotein fraction of some plants (Thompson et al, 1964;Dunnill and Fowden, 1967) prompted us to prove intermediacy of this amino acid for the biosynthesis of CPOAA. This paper concerns the synthesis and the in vivo incorporation of intermediate amino acids.…”

The Identification of 5-Hydroxyl-L-norvaline in Cultures of Pyridoxine Auxotrophs of Escherichia coli B

“…Chemical synthesis of 5-hydroxynorvaline.-The individual d and l isomers of 5-hydroxynorvaline were prepared from D-and L-glutamic acid, respectively, by esterification (27) and reduction of the resulting 5-ethyl esters (10,28,29).…”

“…Although 5-hydroxynorvaline is a known constituent in the seeds of higher plants [Jack Bean (10) and Astragalus species (11)] and is a component of humilixanthin, a betalin isolated from the fruits ofRivina humilis (12), it has not been described as a natural product occurring in microorganisms. We now report, however, that pyridoxine-starved cultures of two pyridoxine auxotrophs of Escherichia colt B produce 5-hydroxy-Lnorvaline in quantities similar to those of common protein amino acids found in these cultures.…”